A CT system is one that takes a series of 2D radiographs of an object or person as the part or person rotates relative to the radiography system (e.g. an X-ray source and imaging system). These images are known as a “set of projections”. The CT system then uses the projections and creates a 3D data set known as a “volume data set”. The creation of the 3D data set is known as “reconstruction”. This data set can be viewed in many ways, but primarily thin sections of the data set are used to create images known as “slices”.
One purpose of a CT system is to provide slices of an object or specimen, such as providing slices of a patient's brain as part of a medical diagnostic procedure. Another use of a CT system is to provide slices of a manufactured component or system for quality control purposes.
The object can be rotated using a rotatable platform while such object is being imaged. One part of a typical image reconstruction process depends on the center of rotation being aligned with respect to the center of the source of radiation (known as the “spot”) and the center of the detector. Portions of the resulting reconstructed image may be difficult to reconstruct properly due to various reasons, including an undesirable offset in the center of rotation. Blurring of features of the object will then occur during reconstruction.
In view of the foregoing, improved center offset calibration techniques for image analysis for CT systems would be beneficial.